Wonder Bar Fuse

[Frank B.]

My wonderbar radio quit working in mid-sentence and the fuse,wiring and power/ground to the radio are all good.
Question, before I pull it out, is there a "last Chance" fuse that any body knows about inside these radios?

[Jack H.]

Re: Wonder Bar Fuse

Sure! It's well documented in the Delco Radio Repair Manual that there's a protection device built into the radio's circuitry (fuse resistor) that's in addition to the vehicle's external branch circuit fuse. Unfortunately, you have to pull the radio from the car, crack open the case, and test/probe verify the fuse resistor...

That means you need to be a bench tech with approriate supporting documentation, test equipment and electrical skill/knowledge.

[Frank B.]

Re: Wonder Bar Fuse

Thanks Jack,, That info moves me forward. I have some experience, and know sources with the knowledge and tools, but not the shop manual.
Will investigate further, and maybe send it back to Charles S.

[Dan D.]

Re: Wonder Bar Fuse

The fuse resistor Jack talks about is there to protect the radio circuity if the DS-503 output transistor shorts out. Those were very old technology germanium transistors and were very prone to failure. It is possible that just the fuse resistor opened up, but more than likely the device is gone as well. -Dan-